What you provide
What you provide
- Side a, using the same scenario as the other inputs
- Side b, using the same scenario as the other inputs
- Included angle C expressed in deg, using the same scenario as the other inputs
MATH / TRIGONOMETRY
Law of Cosines Calculator
Solve the third side from two sides and their included angle. Review the equation, substituted values, result context, and modelling limits in one guided workspace.
- 01 Calculated in this tab
- 02 Values stay in this browser tab
- 03 Use boundary
Use boundary
Calculation path
Solve the third side from two sides and their included angle. The page evaluates the displayed equation from your supplied values and presents both symbolic and substituted KaTeX working so the arithmetic can be checked.
Calculation path
c = sqrt(a^2+b^2-2ab cos(C))
What you receive
What you receive
- Solved side c from the stated equation
- A symbolic formula plus substituted working with your values
- Visible assumptions, field guidance, and an authoritative learning reference
Use boundary
Choose the maximum decimal places shown. This does not increase source accuracy.
The two supplied lengths and included angle must describe one Euclidean triangle.
Use internally consistent units and retain extra precision when carrying the result into another calculation.
Reviewed reference factors